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Alzheimer’s disease: Vaccines linked to reduced risk

A man in a mask getting a vaccine.

Nov. 6, 2023—If you've been putting off your flu vaccine this year, there may be an extra reason to get it done. Getting your shots is linked to a lower risk for Alzheimer's disease, a form of dementia, according to recent research in the Journal of Alzheimer's Disease.

The flu vaccine isn't the only immunization linked to a lower risk for Alzheimer's. Research has linked a lower risk for dementia with vaccines against:

  • Flu.
  • Pneumococcal disease (pneumonia).
  • Herpes zoster (shingles).
  • Tetanus, diphtheria and pertussis.
  • Polio.

Benefits of getting your shots, by the numbers

A 2022 study used a database of health insurance claims to compare people age 65 and older who got their flu vaccine with those who did not. A similar study in 2023 compared people who received other vaccines—for tetanus, diphtheria, pertussis (whooping cough), shingles and pneumonia—with those who did not. Their findings might motivate you to roll up your sleeve:

  • People who got a flu vaccine during a four-year period were 40% less likely to get Alzheimer's compared to those who didn't get vaccinated.
  • People who consistently got their flu shot reduced their risk of Alzheimer's by almost 6% compared to people who didn't.
  • Zostavax (a shingles vaccine) may have prevented 1 in 5 new cases of dementia among older adults during a seven-year period.
  • Only 7.9% of people who got the pneumococcal vaccine got Alzheimer's, compared to 10.9% of those who didn't get the shot.
  • Those who got the pneumococcal vaccine between the ages of 65 and 75 cut their Alzheimer's risk by 25% to 30%.

More research is needed

These results are nothing to sneeze at. But scientists still aren't sure what causes Alzheimer's. And they don't know exactly how vaccines may protect against Alzheimer's.

One possibility has to do with how the immune system and inflammation affect brain health. Diseases that cause inflammation have been associated with cognitive decline. Some researchers think that preventing illness in the first place might help prevent Alzheimer's. It's also possible that vaccinations might make the immune system better at getting rid of the plaque that builds up in the brain to cause Alzheimer's.

Researchers are working to test these and other theories. But more study is needed to clear up the unknowns.

It's not too late to get your flu shot

Even if it turns out that vaccines don't protect your brain from Alzheimer's, they do offer protection from diseases like flu and shingles. Preventing those diseases is well worth doing for its own sake. So make sure to stay up-to-date on all the vaccines your doctor recommends—including this year's flu and COVID-19 vaccines.

Sources

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